Recommendations for the Ready Mixed Producer

Do not use calcium chloride with color pigments. It tends to cause discoloration/blotches

Keep all raw materials — cement, sand and aggregates especially — as consistent as possible throughout the entire project. Any change can affect the final color of the project.

Be sure concrete loads have consistent mix times, and that delivery and discharge times are a quick as possible. Overmixing, longer that 1-1/2 hours affects color consistency.

Air content, especially in freeze/thaw climates, should be 5-7%. Air entrainment is only necessary if your climate dictates

Slump should be consistent and less than 5 inches (125 mm).

Water has a tremendous effect on the final color. Too much water tends to lighten the color of the project — it looks "pale" or "washed out". If better flowability is required, use a plasticizer or water reducing admixture instead.

Clean mixer thoroughly at the end of the job. Begin each new color with a clean drum.

Do not overload the mixer as this reduces mixing efficiency. By the same token, mixer should be loaded to a minimum of 40% capacity for a good color mix.

Recommendations for the Contractor Using Colored Ready Mix

Integrally colored concrete is installed the same way uncolored concrete is. Follow normal procedures regarding base preparation, use of vapor barriers, placement of forms, reinforcement and joints. But there are some things that should be observed.

Be sure to use an experienced ready mixed supplier who consistently follows the recommendations provided above.

Do not sprinkle dry concentrated pigment onto the surface of "green" concrete.

Give yourself enough time and adequate labor to do the job right.

Stop floating the concrete when surface becomes wet. Then begin troweling after bleed water evaporates. If you wait too long, burns or dark spots are likely.

Avoid adding extra water at the job site. Also, don't wet finishing tools or sprinkle any water onto the surface of the colored concrete.

Final finishes, such as broom, swirl, rough or imprinting, usually result in a more uniform color appearance then smooth surfaces.

Do not fog or cover final project with plastic sheets. This tends to create uneven colors.

Curing compounds are recommended but extreme care must be taken in their selection and application. Also, surface retarders during finishing may be necessary in dry, windy weather. For both products, consult your local ready mixed concrete or admixture supplier for information on products recommended for colored concrete.

Efflorescence is a naturally occurring phenomenon. It is that white powdery substance, and unfortunately it is more visible on colored concrete products. Sometimes the whole project looks lighter due to an even layer of efflorescence. Other times, it occurs in spots or in areas around the edges where faster setting occurred. If efflorescence happens, care should be taken for its removal. Use a reputable product and follow recommendations carefully, using all safety precautions.